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2003.2.19
IDEMA-JAPAN
Assesment of AV Lite Feature
for ATA-7
IDEMA – JAPAN
Consumer HDD Committee
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Intention of IDEMA-JAPAN
2003.2.19
IDEMA-JAPAN
• IDEMA-JAPAN consumer HDD committee appreciates T-13
activities.
• Companies of IDEMA-JAPAN committee member really need to
standardize AV command. To reject confusion and to get
compatibility of manufactures and generation on HDD.
• IDEMA-JAPAN consumer HDD committee agrees basic concept
of current ATA-7 AV commands. However IDEMA-JAPAN
consumer HDD committee requests some modification to avoid
misunderstanding as well as to use them effectively.
• IDEMA-JAPAN understand Command completion within the
Time Limit should always have priority.
• These comments to follow are discussed by IDEMA-JAPAN
consumer HDD committee's Sub WG members;
Toshiba, Hitachi, JVC, Matsushita, Sanyo, SONY, Pioneer,Orion
Maxtor Japan, Seagate Japan, Western Digital Japan, Fujitsu,
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IDEMA-JAPAN’s point of View
2003.2.19
IDEMA-JAPAN
# IDEMA-JAPAN considers
ensuring compatibility between manufacturers and generations on
HDD consumer use will encourage broad acceptance of HDD in the
CE market.
# We appreciate your reflecting IDEMA-JAPAN’s ideas in Streaming
feature set at ATA committee in Oct. 2002
# However, responding to AV Lite proposed by Seagate being
incorporated in ATA7 draft at ATA committee in Dec. 2002,
IDEMA-JAPAN made an assessment on AV Lite.
1) Comparison between AV Lite and AV Stream commands
2) IDEMA-JAPAN’s stance on this matter
As above, we would like to make IDEMA-JAPAN consensusbased requests to ATA committee.
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2003.2.19
IDEMA-JAPAN
AV-Lite vs Streaming Feature Set
Comparison 1
Function In AV-Lite, when
AV-Lite
Streaming Feature Set
a stream error
occurs, a required amount of data
after timer expires.
Stream IDis transferred
Not Supported
CONFIGURE STREAM
InAV-Lite,
Streaming
Feature Set,
a READ/WRITE STREAM
In
Continuous
Mode
required
amount of data only
is
can
be
enabled/disabled
CCTL transferred
SET
FEATURES
STREAM
Stream
IDCCTL.
becomes a CONFIGURE
powerful
within
by Set Features
Command. multiple
tool inCase
controlling
Worst
Timer
READ/WRITE STREAM
Streaming
Feature
Set
can
streams with different data
Timer Setting
A Group
of
Each Stream I/O Command
control the
state
of
Continuous
transfer
rates.
AV-Lite does not
Commands
Mode
In Streaming
in each
Streaming
Feature
Set,
I/O each Stream ID
support
this function.
Command.
can have
an independent
andofRead
Timer Expiration
Transfer
of required CCTL,
Transfer
required amount
and Write
operations
with different
CCTLs
and Stream Data
amount
of data after
of data
within CCTL
can be
carried
out.
Urgent
Mode
is supported
onlyTimer
in acts
In AV-Lite,
Worst Case
Timer
Expiration
In on
theacase
of of
AV-Lite,
a single CCTL
Streaming
Feature
Set.（Optional）
group
AV commands,
while
Continuous
SET
FEATURES
READ/WRITE
STREAM
configured
by on
Setan
Features
command is
CCTL acts
individual
Mode applied to
Error
Handling
Continuous Bit
all AV
Commands.
streaming
command
in Streaming
Urgent
NotSet.
Supported
READ/WRITE STREAM
Feature
Mode
Urgent Bit
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2003.2.19
IDEMA-JAPAN
AV-Lite vs Streaming Feature Set
Comparison 2
Function
Cache
Control
Handle
Streaming
Error
DMA
PIO
Stream Log
AV-Lite
Streaming Feature Set
Streaming Error Log
AV-Lite
does
supportSTREAM
PIO
Transfer
isnot
supported
FLUSHDMA
CACHE
READ/WRITE
function
is
supported
by
transfer.
However,
PIO
transfer
by both proposals.
AV-Lite
Not proposals.
Sequential/Flush
Bit
both
mode
can be
effective in lowuses
already
existing
Not Supported
READ STREAM
cost applications.
commands
while Stream
In AV-Lite, Flush Cache
Handle
Streaming
Feature Set uses
a new
set of Error
Command is used for cache
commands
control. Streaming Feature Set
READ/WRITE
READ/WRITE STREAM
has cache control bits in all
DMA
DMA （EXT）
Streaming
Feature
Set can
Streaming
I/O
Commands
and
it
resume
suspended
Error
Not Supported
provides
increased READ/WRITE
flexibility in STREAM
Recovery
Procedures by setting
AV data control.
PIO
Handle Streaming Error bit. AVREAD
LOGnot
EXT
READ LOG EXT
Lite does
have an equivalent
function.
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2003.2.19
IDEMA-JAPAN
AV-Lite vs Streaming Feature Set
Comparison 3
SET FEATURES
IT
CCTL
Continuous Mode
READ/WRITE DMA （EXT）
IT
Continuous
Not Continuous
CONFIGURE STREAM
Stream ID/Default CCTL
Allocation Unit
READ/WRITE STREAM DMA
Flush Cache
Continuous
Urgent
Not Continuous Not Urgent Not Sequential
HSE
Stream ID / CCTL
FLUSH CACHE
READ/WRITE STREAM PIO
READ LOG EXT
Continuous
Flush Cache
Urgent
Not Continuous Not Urgent Not Sequential
Stream ID / CCTL
HSE
READ LOG EXT
IT Area
AV-Lite
AV Area
Streaming Feature Set
Common Area
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2003.2.19
IDEMA-JAPAN
Assesment-1 Summary of AV-Lite Feature
1
2
Independent CCTLs for
Read and Write
(Concept of Stream ID)
Streaming
Feature Set
AV-Lite
Possible Problem in AV-Lite
Supported
Not
Supported
There exists a product which requires
more clear CCTL management and R/W
independent CCTL.
Not
Supported
When Stream Error occurs while
accessing Meta Data (IT Data),
1)Non-zero Worst Case Timer (AV Mode)
→Impossible to recover data
2)Zero Worst Case Timer (IT Mode)
→Streaming failure
Not
Supported
1)HDD
→Cache Control can be Optimized.
2)Set
→Read Look-ahead operation is
carried over to the following
command execution.
Supported
From now on, High-End HDDs become
over 137GB and software designed for
High-End HDD will be also used for
Low-End HDDs (Less than 137GB). So,
48bit LBA mode will not be a problem.
Read Stream Setting
(HSE bit)
Supported
3
Read Stream Setting
(NS bit)
Supported
4
Max 128KB
Access Mode
Not
Supported
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2003.2.19
IDEMA-JAPAN
AV-Lite vs Streaming Feature Set Comparison
Timer Setting & Management CCTL
(Streaming Featute Set)
Relation between CMD,Time Period,and R/W Data Size are Clear
CCTL1
Com1
Successful Cmd Comp
Cmd comp, ERR=0, SE=0
CCTL2
Com2
Stream Error
All Data Transfer
Com3
X
CC, ERR=0, SE=1
CCTL3
CCTL Out Error
Not All Data Transfer
Data
Residue
X
CC, ERR=0, SE=1,CCTO=1
Com4
Cmd Comp &Status Report Timing
(Continuous Mode)
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2003.2.19
AV-Lite vs Streaming Feature Set Comparison
IDEMA-JAPAN
Timer Setting & Management CCTL
(AV Lite)
Relation between CMD,Time Period,and R/W Data Size are not Clear
Flash Cash
Grp1
FC
Worst Case Timer Limit
C1 C2
Arm Start
Timer Timer
Grp2
… Cm
Successful Cmd Comp
WCTL
SE=0
Stream Error
All Data Transfer
FC
…
C1 C2
Cn
X
Unknown
data
Timer
Expires SE=1
Arm
Start
Timer Timer
WCTL
Grp2’
Stream Error
FC
Not Many Data Transfer
C2
X…
C1 C2
Arm
Start
Timer Timer
Timer
Expires SE=1
・Command completion within WCTL is not guaranteed.
・Device has no knowledge of the total number of commands,
toal sector count to be issued in a group of commands.
Cmd Comp
Status Report Timing
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2003.2.19
AV-Lite vs Streaming Feature Set Comparison
IDEMA-JAPAN
Timer Setting & Management CCTL
(AV Lite)
Relation between CMD,Time Period,and R/W Data Size are not Clear
HDD
System
WCTL
FC
C1 C2
… Cm
WCTL
FC
C1
C2
System only know
total number of commands
toal sector count
…
Device only know
each CMD’s parameter
can not know Desired behavior
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2003.2.19
IDEMA-JAPAN
Why Independent CCTLs is needed ?
1.Basic Case:Same CCTL
write
System Buffer
ex. 2MB
X+1sec
Xsec
500msec
write
SD Stream
ex.8Mbps
(1MB/S)
1MB
HDD
Read
Read
SD Stream
ex.8Mbps
(1MB/S)
1MB
System Buffer
ex. 2MB
Allocation unit
1MB
2.Actual Case:Different CCTL(stream ID must need)
HD Stream write
ex.16Mbps
(2MB/S)
System Buffer
ex. 4MB
Xsec
write
X+1sec
800msec
2MB
HDD
Read
LD Stream
ex.4Mbps
(0.5MB/S)
Read
0.5MB
System Buffer
ex. 1MB
Allocation unit
0.5,1,2MB
Multi Allocation Unit
PVR can realize Good responce
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2003.2.19
IDEMA-JAPAN
Why HSE bit is needed ?
3.Actual Case-2:CCTL+Handle Stream error
System Buffer
ex. 2MB
Xsec
write
SD Stream
ex.8Mbps
(1MB/S)
SD Stream
ex.8Mbps
(1MB/S)
or
PC Data
（EPG）
First R/W
write
HDD
Read
Allocation unit
1MB
2ns
3rd
R/W
R/W
W/HSE W/HSE
Error Recovery Tryal
500msec
1MB
Read
System Buffer
ex. 3MB
X+1sec
X+2sec
500msec
1MB
X
1MB
X
1MB
Read again
HSE=1
In Stream Recording case ,even If error is
occurred,when Host system prepares extra
buffer,In that case HSE bit wil be effective.
also PC Data R/W case too.
However if HSE bit does not supported,
that error will be unrecovered for ever untill
another write streem will be finished
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2003.2.19
IDEMA-JAPAN
Assesment-2 Summary of AV-Lite Feature
• All functions of AV-Lite are included in Streaming Feature Set.
• AV-Lite cannot set independent CCTLs for Read and Write.
- Streaming Feature Set can 1) Independent CCTLs with each stream ID
2) Definition of CCTL is clear
Limited flexibility in handling multiple AV stream
– When handling multiple streams with different data transfer rates, Set
Features Command must be issued every time CCTL changes.
Streaming Feature Set can handle multiple streams effectively by using
Stream ID.
• AV Lite lacks features which are important in handling both
AV stream and PC Data simultaneously.
– e.g.) Handle Streaming Error Bit→This function increases the possibility
of data recovery by resuming suspended ERP. AV-Lite does not support
this function.
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2003.2.19
IDEMA-JAPAN
Overview of AV-Lite &Streaming Feature Set
Streaming
Feature Set
AV Lite
’99
’00
PVR First Generation
Simple Recording
AV Lite had been fittable
’01
’02
’03
Next PVR/Home server Generation
Increasing more function
Streaming Future Set should be a must
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2003.2.19
IDEMA-JAPAN
The result of assessment by IDEMA-JAPAN
Conclusions
Only AV Stream command set should be a standard,
with AV Lite removed
Reasons
1) AV Lite proposed by Seagate does not work adequately to
AV applications from now.
2) The presence of two kinds of AV cmd cause negative effects.
- Cause confusion in the CE market with compatibility matter of
software of AV set.
- Low functional AV Lite cannot be used for inheritable recorder
software’s command in AV set using next generation HDD,
and cannot realize compatibility between generations.
- The simplicity of AV-Lite seems to make HDD firmware evelopment
easier. However, its function is too limited to satisfy increasing
complexity of AV CE. Thus, it soon forces HDD Manufacturers to
make extra efforts to implement AV Stream command set, too.
- For the above reasons, AV Lite should not be standardized.
Basics: Only one kind command should be standardized.
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Appendix-1
2003.2.19
IDEMA-JAPAN
IDEMA-JAPAN assessment by member company
SET Vendor
Function
• Application burdened with frequently issuing
the Set Feature command
•
• Disadvantage of not supporting PIO mode
from the system cost stand point
• Disadvantage of not supporting Stream IDs
when supporting multiple stream structure on
Application
•Insufficiency of maximum time out value (2.5s)
•Incapability to handle the time limitation
because of uncertainty of the timing of issuing
a Flush cache command from Host
Flexibility
• No compatibility with feature AV function
because of no plan of extending AV Lite
function
Standardization
• Confusion of two AV standards for developing
applications in the market
• No necessity of the 28bit addressing in AV
function if supporting the 48bit addressing for
HDDs with capacity less than 137GB
HDD Vendor
HDD Implementation & Test
•Difficulty of supporting both AV functions
because of Program size limitation of HDDs,
but depending on customer’s demand
•A burden of double resources for HDD
tests
• A burden of evaluation resource of each
application according to each PC driver for
each AV standard
• Possibility of two deferent models with
each AV function, but considering avoid of
supporting both AV functions concerning
the trend of PC application
• Although supporting 28bit addressing for
current systems, no need of 28bit
addressing AV function for next models
because of implementation of 48bit
addressing without 128KB transfer
limitation
•Already Customer using AV Lite exists.
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